1. Field of the Invention
The present invention relates to a method for reducing damage caused by one-ring scam phone calls to a communication terminal.
2. Description of the Related Art
In recent years, a caller ID function, which notifies a telephone number (a caller ID) of a calling side to a called side, has been provided in a common telephone. A called side telephone provided with the caller ID function displays a notified caller ID on a display, and stores the caller ID in a call registry. Accordingly, a user of the telephone is able to know who the calling side is on the basis of a displayed caller ID, without answering the phone. Also, a user is able to call back later using a telephone number stored in a call registry, if s/he cannot take a call.
Recently, however, there have been many cases of a caller ID function being abused by people who make one-ring scam phone calls (scammers), who most commonly target mobile phones. A one-ring scam phone call is an act of leaving a caller ID in a call registry of a called side and thereby leading a user of the called side to respond to an unintended pay-service.
Specifically, a scammer calls a mobile phone and hangs up immediately after one ring, thereby leaving the caller's telephone number in a call registry of the mobile phone, without being answered by a called side. If the user of the mobile phone calls back using the telephone number in the call registry, s/he is connected to an unintended pay-service. In the case of a mobile phone especially, the call back function is readily used as it is not only convenient but also necessary because a user may often not be able to answer a call, for example, while driving, or during a meeting. Therefore, mobile phone users would call back a telephone number stored in a call registry carelessly or unwittingly, and thereby become an easy target of one-ring scam phone calls.
Countermeasures to a one-ring scam phone call have been proposed by six Japanese unexamined patent publications: JP 2003-125066; JP 2004-048344; JP 2004-056324; JP 2004-120243; JP 2004-135124; and JP 2004-134903 which is to not store a caller ID of a phone call in a call registry that is not registered in a phonebook of a called mobile phone. This countermeasure is based on a belief that a call from a telephone not registered in a phonebook of a called mobile phone is likely to be a one-ring scam phone call, and by not storing a caller ID of such a call, a user would be prevented from calling back an unintended pay-service.
In contrast to the countermeasure, an aspect of the present invention proposes a method for preventing a one-ring scam phone call from being repeated. Specifically, an aspect of the present invention proposes a method of, when replying to, possibly a one-ring scam phone call, preventing a caller ID of a user from being notified to the scammer. This method is effective in preventing a one-ring scam phone call from being repeated, because if a caller ID is not notified to a scammer, s/he is not able to know for a fact whether a particular caller ID is actually being used.
Usually, a scammer causes a computer to generate caller IDs at random and dial the caller IDs without knowledge of whether the caller IDs are actually in use. However, once a scam-call is replied to with a user' caller ID attached, the scammer comes to know that the caller ID is in use and can repeatedly use the caller ID for scam phone calls. For this reason, preventing a scammer from knowing that a caller ID is in use can be a countermeasure to repeated one-ring scam phone calls.
The problem addressed by the present invention applies also to an email. As in the case of a phone call, a reply mail to a scammer with an email address attached may lead to a situation where a user is bombarded with unsolicited mails.